5I.15 (ignoring solid)

[Ashley Hiti 1K]

Why can we ignore the solid in this problem? Or more generally why can we ignore the solid when calculating concentration?

[Jose Angelo Grajeda 2D]

I believe this is because in their concentrations remain relatively unchanged during the equilibrium reaction. This property extends to pure solids, pure liquids, and solvents, and the explanation is most easy to think about with solvents, because in an equilibrium reaction, the solvent on the reactant side and on the product side remains relatively constant (in excess, so the equilibrium reaction will not produce much change); and likewise, the amount of pure solid/pure liquid does not change significantly during an equilibrium reaction. Hope this helps!